MBio Diagnostics, Inc. proposes to develop a low-cost, point-of-care (POC), HIV-1/2 antigen/antibody combination diagnostic device. The goal is for the Ag/Ab combo system to deliver the performance of laboratory based, 4th generation antigen/antibody clinical analyzers, in a POC platform with cost and workflow of the widely used HIV rapid tests. Phase I research and development met or exceeded stated technical milestones. In particular, the MBio HIV antigen and antibody assays provided a combined performance that significantly exceeds performance FDA approved rapid tests, and provides near equivalence to much more complicated laboratory based tests. HIV infection remains a major public health crisis both in the United States and worldwide. There is increasing awareness that acutely infected individuals disproportionately contribute to disease spread. Yet these individuals remain the most difficult to identify, as infectivity is highest prior to the appearance of the HIV antibodies that serve as the basis for serological diagnostics. There are currently no FDA-approved point-of-care (POC) tests that directly target HIV viral antigens. An HIV-1 antigen/antibody (Ag/Ab) combination assay - the so-called 4th generation immunoassay - in an inexpensive, simple to use, POC format would fundamentally improve HIV-1 screening efforts in the United States and worldwide. The specific aims of this proposal are to: (1) Combine the Phase I p24 antigen detection assay with the MBio multiplexed serology assay cartridge, addressing issues of final monoclonal antibody (mAb) pair selection, HIV-1 Ag and HIV-2 Ag selection, reagent conjugations, cross-reactivity, and minimization of assay steps and complexity. (2) Modify the MBio Cartridge, Rack, Reader, and Software to deliver an automated HIV-1/2 Ag/Ab combo result, and incorporate heat stable assay reagents into the MQ cartridge. The Aim 2 milestone is a portable, integrated system delivered to clinical collaborators that meets FDA CLIA waiver guidance requirements. (3) Validate system using well characterized early HIV infection specimens including a panel of 200 HIV positive specimens comprised of 20 acute infection samples, early seroconversion, and seropositive samples. 200 HIV-negative samples will be used for specificity testing. (4) Place systems in an intended use setting and capture operational and usability feedback in advance of design lock, and to use this site to generate a preliminary dataset on capillary whole blood samples. The outcome of this program will be a system design and dataset for an FDA investigational device exemption (IDE) meeting in advance of clinical trials.